The present invention relates to an improvement in circular ladies hosiery knitting machinery adapted to simultaneously knit yarn and introduce terry to the knitted product.
Techniques and equipment for terrying a fabric produced by circular knitting machines are well known. Examples of such arrangements are those disclosed in U.S. Pat. Nos. 3,107,509, issued to Glen R. Farmer on Oct. 22, 1963 and 4,010,626, which was granted to Tibor Feher on Mar. 8, 1977.
In each of the two patents just identified, a rotatable dial is employed which is coaxial with, and operatively related to, a rotatable needle cylinder. The cylinder houses needles which are arranged for up-and-down motion as the cylinder rotates. The reciprocating needles engage yarn so as to knit the fabric. The dial supports a plurality of radially arranged loop-forming elements which are selectively extended to a position proximate the path of reciprocation of the needles whereby during downward movement of the needles, a length of yarn is engaged and is drawn into engagement with the elements. Continued downward needle movement results in loops of yarn being formed. The elements are configured such that upon their retraction into the dial, the loops are released, thereby forming terry in the knitted fabric.
During fabrication of a product such as a pantyhose with knitted waistband, it is also desirable to form loops which are knitted directly into the fabric rather than serving as terry. This requires that a previously formed loop be positioned in the path of needle movement so that the loop is engaged by the needle and drawn into the next course of fabric being knitted.
Such a procedure is not possible with terrying arrangements of the type disclosed, for example, in U.S. Pat. No. 3,107,509 inasmuch as the verge bit has essentially a smooth, straight upper surface. Once a loop is formed and the verge bit is withdrawn prior to be re-extended for introduction of the loop to the next course, the verge bit withdrawal results in the loop slipping off the end of the verge bit.
One of the embodiments disclosed in U.S. Pat. No. 4,010,626 attempts to solve this problem by utilizing a pair of loop-forming elements having been modified, one with the tip completely cut off and the other one, the tip modified. When terry is to be formed, full retraction of the pairs of loop-forming elements into the dial causes the loop to be removed from the jacks. With such an arrangement, the loop-forming element can only do terrying, it cannot do the job of a regular transfer jack making a knitted waistband on ladies pantyhose.
It is apparent that the arrangement of U.S. Pat. No. 4,010,626 described in the preceding paragraph has important shortcomings. For example, such a device requires a pair of loop-forming elements and complicated camming is necessary to provide both partial and full withdrawal of the loop-forming elements.